Zip by its standard only allow for 7bit characters.
But there are settings to force what code page to use. They are still "experimental" (not widely tested) so you have to type the settings in the command line field
* Force the zip filesystem to use a custom codepage. Set Codepage using ":zipcp <cp num>" in the command line field. ( type ":zipcp -1" for current system codepage )
":zipcp 0" to restore to default behavior
* Force the zip filesystem to use the extended zip support for UTF8 when created Zip archive. Use commandline command ":ziputf8 1" to enable and ":ziputf8 0" to disable